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diff --git a/rust.html.markdown b/rust.html.markdown new file mode 100644 index 00000000..b2854b0c --- /dev/null +++ b/rust.html.markdown @@ -0,0 +1,307 @@ +--- +language: rust +contributors: + - ["P1start", "http://p1start.github.io/"] +filename: learnrust.rs +--- + +Rust is a programming language developed by Mozilla Research. +Rust combines low-level control over performance with high-level convenience and +safety guarantees. + +It achieves these goals without requiring a garbage collector or runtime, making +it possible to use Rust libraries as a "drop-in replacement" for C. + +Rust’s first release, 0.1, occurred in January 2012, and for 3 years development +moved so quickly that until recently the use of stable releases was discouraged +and instead the general advice was to use nightly builds. + +On May 15th 2015, Rust 1.0 was released with a complete guarantee of backward +compatibility. Improvements to compile times and other aspects of the compiler are +currently available in the nightly builds. Rust has adopted a train-based release +model with regular releases every six weeks. Rust 1.1 beta was made available at +the same time of the release of Rust 1.0. + +Although Rust is a relatively low-level language, Rust has some functional +concepts that are generally found in higher-level languages. This makes +Rust not only fast, but also easy and efficient to code in. + +```rust +// This is a comment. Single-line look like this... +/* ...and multi-line comment look like this */ + +/////////////// +// 1. Basics // +/////////////// + +// Functions +// `i32` is the type for 32-bit signed integers +fn add2(x: i32, y: i32) -> i32 { + // Implicit return (no semicolon) + x + y +} + +// Main function +fn main() { + // Numbers // + + // Immutable bindings + let x: i32 = 1; + + // Integer/float suffixes + let y: i32 = 13i32; + let f: f64 = 1.3f64; + + // Type inference + // Most of the time, the Rust compiler can infer what type a variable is, so + // you don’t have to write an explicit type annotation. + // Throughout this tutorial, types are explicitly annotated in many places, + // but only for demonstrative purposes. Type inference can handle this for + // you most of the time. + let implicit_x = 1; + let implicit_f = 1.3; + + // Arithmetic + let sum = x + y + 13; + + // Mutable variable + let mut mutable = 1; + mutable = 4; + mutable += 2; + + // Strings // + + // String literals + let x: &str = "hello world!"; + + // Printing + println!("{} {}", f, x); // 1.3 hello world + + // A `String` – a heap-allocated string + let s: String = "hello world".to_string(); + + // A string slice – an immutable view into another string + // This is basically an immutable pointer to a string – it doesn’t + // actually contain the contents of a string, just a pointer to + // something that does (in this case, `s`) + let s_slice: &str = &s; + + println!("{} {}", s, s_slice); // hello world hello world + + // Vectors/arrays // + + // A fixed-size array + let four_ints: [i32; 4] = [1, 2, 3, 4]; + + // A dynamic array (vector) + let mut vector: Vec<i32> = vec![1, 2, 3, 4]; + vector.push(5); + + // A slice – an immutable view into a vector or array + // This is much like a string slice, but for vectors + let slice: &[i32] = &vector; + + // Use `{:?}` to print something debug-style + println!("{:?} {:?}", vector, slice); // [1, 2, 3, 4, 5] [1, 2, 3, 4, 5] + + // Tuples // + + // A tuple is a fixed-size set of values of possibly different types + let x: (i32, &str, f64) = (1, "hello", 3.4); + + // Destructuring `let` + let (a, b, c) = x; + println!("{} {} {}", a, b, c); // 1 hello 3.4 + + // Indexing + println!("{}", x.1); // hello + + ////////////// + // 2. Types // + ////////////// + + // Struct + struct Point { + x: i32, + y: i32, + } + + let origin: Point = Point { x: 0, y: 0 }; + + // A struct with unnamed fields, called a ‘tuple struct’ + struct Point2(i32, i32); + + let origin2 = Point2(0, 0); + + // Basic C-like enum + enum Direction { + Left, + Right, + Up, + Down, + } + + let up = Direction::Up; + + // Enum with fields + enum OptionalI32 { + AnI32(i32), + Nothing, + } + + let two: OptionalI32 = OptionalI32::AnI32(2); + let nothing = OptionalI32::Nothing; + + // Generics // + + struct Foo<T> { bar: T } + + // This is defined in the standard library as `Option` + enum Optional<T> { + SomeVal(T), + NoVal, + } + + // Methods // + + impl<T> Foo<T> { + // Methods take an explicit `self` parameter + fn get_bar(self) -> T { + self.bar + } + } + + let a_foo = Foo { bar: 1 }; + println!("{}", a_foo.get_bar()); // 1 + + // Traits (known as interfaces or typeclasses in other languages) // + + trait Frobnicate<T> { + fn frobnicate(self) -> Option<T>; + } + + impl<T> Frobnicate<T> for Foo<T> { + fn frobnicate(self) -> Option<T> { + Some(self.bar) + } + } + + let another_foo = Foo { bar: 1 }; + println!("{:?}", another_foo.frobnicate()); // Some(1) + + ///////////////////////// + // 3. Pattern matching // + ///////////////////////// + + let foo = OptionalI32::AnI32(1); + match foo { + OptionalI32::AnI32(n) => println!("it’s an i32: {}", n), + OptionalI32::Nothing => println!("it’s nothing!"), + } + + // Advanced pattern matching + struct FooBar { x: i32, y: OptionalI32 } + let bar = FooBar { x: 15, y: OptionalI32::AnI32(32) }; + + match bar { + FooBar { x: 0, y: OptionalI32::AnI32(0) } => + println!("The numbers are zero!"), + FooBar { x: n, y: OptionalI32::AnI32(m) } if n == m => + println!("The numbers are the same"), + FooBar { x: n, y: OptionalI32::AnI32(m) } => + println!("Different numbers: {} {}", n, m), + FooBar { x: _, y: OptionalI32::Nothing } => + println!("The second number is Nothing!"), + } + + ///////////////////// + // 4. Control flow // + ///////////////////// + + // `for` loops/iteration + let array = [1, 2, 3]; + for i in array.iter() { + println!("{}", i); + } + + // Ranges + for i in 0u32..10 { + print!("{} ", i); + } + println!(""); + // prints `0 1 2 3 4 5 6 7 8 9 ` + + // `if` + if 1 == 1 { + println!("Maths is working!"); + } else { + println!("Oh no..."); + } + + // `if` as expression + let value = if true { + "good" + } else { + "bad" + }; + + // `while` loop + while 1 == 1 { + println!("The universe is operating normally."); + } + + // Infinite loop + loop { + println!("Hello!"); + } + + ///////////////////////////////// + // 5. Memory safety & pointers // + ///////////////////////////////// + + // Owned pointer – only one thing can ‘own’ this pointer at a time + // This means that when the `Box` leaves its scope, it can be automatically deallocated safely. + let mut mine: Box<i32> = Box::new(3); + *mine = 5; // dereference + // Here, `now_its_mine` takes ownership of `mine`. In other words, `mine` is moved. + let mut now_its_mine = mine; + *now_its_mine += 2; + + println!("{}", now_its_mine); // 7 + // println!("{}", mine); // this would not compile because `now_its_mine` now owns the pointer + + // Reference – an immutable pointer that refers to other data + // When a reference is taken to a value, we say that the value has been ‘borrowed’. + // While a value is borrowed immutably, it cannot be mutated or moved. + // A borrow lasts until the end of the scope it was created in. + let mut var = 4; + var = 3; + let ref_var: &i32 = &var; + + println!("{}", var); // Unlike `box`, `var` can still be used + println!("{}", *ref_var); + // var = 5; // this would not compile because `var` is borrowed + // *ref_var = 6; // this would not too, because `ref_var` is an immutable reference + + // Mutable reference + // While a value is mutably borrowed, it cannot be accessed at all. + let mut var2 = 4; + let ref_var2: &mut i32 = &mut var2; + *ref_var2 += 2; + + println!("{}", *ref_var2); // 6 + // var2 = 2; // this would not compile because `var2` is borrowed +} +``` + +## Further reading + +There’s a lot more to Rust—this is just the basics of Rust so you can understand +the most important things. To learn more about Rust, read [The Rust Programming +Language](http://doc.rust-lang.org/book/index.html) and check out the +[/r/rust](http://reddit.com/r/rust) subreddit. The folks on the #rust channel on +irc.mozilla.org are also always keen to help newcomers. + +You can also try out features of Rust with an online compiler at the official +[Rust playpen](http://play.rust-lang.org) or on the main +[Rust website](http://rust-lang.org). |